const formatTime = date => {
  const year = date.getFullYear()
  const month = date.getMonth() + 1
  const day = date.getDate()
  const hour = date.getHours()
  const minute = date.getMinutes()
  const second = date.getSeconds()

  return [year, month, day].map(formatNumber).join('-') + ' ' + [hour, minute, second].map(formatNumber).join(':')
}
const formatDate = date => {
  const year = date.getFullYear()
  const month = date.getMonth() + 1
  const day = date.getDate()

  return [year, month, day].map(formatNumber).join('-') 
}
const formatMonth = date => {
  const year = date.getFullYear()
  const month = date.getMonth() + 1

  return [year, month].map(formatNumber).join('-') 
}
const formatYear = date => {
  const year = date.getFullYear()

  return [year].map(formatNumber).join('-') 
}
const formatNumber = n => {
  n = n.toString()
  return n[1] ? n : '0' + n
}
const preMonth = date => {
  var year = date.getFullYear()
  var month = date.getMonth()
  if(month==0){
    year=year - 1;
    month=12;
  }
  return [year, month].map(formatNumber).join('-') 
}
const nowMonth = date => {
  var year = date.getFullYear()
  var month = date.getMonth() + 1
 
  return [year, month].map(formatNumber).join('-') 
}
module.exports = {
  preMonth: preMonth,
  nowMonth: nowMonth,

  formatTime: formatTime,
  formatDate:formatDate,
  formatMonth:formatMonth,
  formatYear:formatYear
}
